There is hereby provided a method comprising: detecting at a first radio node a first signal indicating the number of hops at which a second radio node that transmitted the first signal first detected a second, earlier signal; and deciding whether to transmit said first signal onwards from said first radio node based at least partly on (i) a direction indicator in said first signal, and (ii) a comparison of the respective numbers of hops at which said first and second radio nodes first detected said earlier second signal.